If You Only Knew
by hyper13
Summary: "How come you never try to kiss me?" he countered, and she giggled. It wasn't a stupid giggle that some girls did to make you think they thought you were funny; it was genuine and cute, and he didn't mind it so much. Also known as: The companion piece to "I Hate You, I Love You" that no one asked for. The same story as written from Derek's point of view. Utterly unedited.


_Until they were in Derek's room one evening and she looked up at him and said, "How come you never try to kiss me?" Her head tilting up at him._

 _"How come you never try to kiss me?" he countered, and she giggled. It wasn't a stupid giggle that some girls did to make you think they thought you were funny; it was genuine and cute, and he didn't mind it so much._

 _Also known as: The companion piece to "I Hate You, I Love You" that no one asked for. The same story as written from Derek's point of view. Utterly unedited as I got lazy/ran out of time and didn't want to postpone posting it anymore._

 _(Rating is for an implied adult scene)._

* * *

No one was more surprised than Derek that he maintained a relationship for three and a half years-practically his entire college existence. Sometimes (frequently) he had thought (hoped) that someone else (Casey) would be the one he settled down with. He had known from the day his dad married Nora that the eldest McDonald child was going to be trouble. And she was. It was like that song from that musical she loves, their relationship was one of "pure, unadulterated loathing."

Sometimes it was hard to forgive his dad for marrying Nora.

He's _pretty_ confident that he hated her in the beginning. She wouldn't give in to his classic smirk and leather jacket, she pushed back, she was annoying, opinionated, and she completely changed the dynamic of their house. Sure, Nora and Lizzie had a little to do with it, but Casey was the one who always pushed for changes with things like her feminist manifesto.

Then she started dating Sam and he _really_ hated her. Sam was _his_ best friend, not hers. Seeing them together made him ill and he tried to avoid them when they were together and it wasn't until they had broken up for good and the sense of satisfaction set in and an unwanted, unprompted thought flitted across his mind: _thank goodness she's single again._ It was during dinner (he remembers, because he nearly choked as his mind decided to prank him) as Casey made the announcement that she and Sam had broken up, for good, and they were friends. He tried to convince himself that he was relieved because it meant none of them were going to have to deal with her break up reactions anymore (can anyone say dramatic?). Honestly, it _was_ a huge part of it, really.

Except then she was dating Max and everything about her changed. She changed her clothes, her laugh, and she wasn't Casey anymore and he was so desperate for that part of her to come back that he pushed harder than normal until he could see some _life_ in her eyes. He'd been worried that she was turning into the same cardboard cutout that Max was, but then there was that fire in her eyes and not long after that she started developing allergies and Max was out of the picture. The relief was immense and the feeling of possessiveness the next time a guy thought of asking her out was intense and he just _knew_ (he's self-aware, and he's always been pretty quick on the uptake). Surprisingly, though, it didn't freak him out like he would have thought being in l-l-love might. Maybe because she was his step-sister and therefore unattainable and Dennis would have his balls before he could even say "I love Casey," so there was no need to be afraid of commitment as there was no actual threat of being committed.

It did put a damper on his dating for a bit, though.

It probably served as some big cosmic joke that the one girl he would fall for would be the one girl that would never love him back.

As the years passed, they grew closer and their fights were less about fighting for dominance and more about him just engraving that passionate expression in his mind forever-it only ever came out for him. He knew Casey best, and he thought, maybe, she lived for those moments, too. He was wrong, of course, but it was nice to dream.

Then she started avoiding him. It was obvious, too. She'd see him coming in the halls and her eyes would go wide and she'd turn around and dart away in the other direction. When she wasn't avoiding him, she'd be sure to use the ugly B word, without the step (a very important prefix, here) in front of it. He thought that maybe she had figured it out and it hurt and he missed fighting with her and so he put honey in her shampoo (and oldie, but a goodie) and she yelled "Der _ek_ ," which was music to his ears by this point and he grinned but she didn't come running into his room to yell at him after she was done, so he had to step up his game and so he started actively seeking her out to annoy her, because he couldn't go on living without her yelling his name, broken in half.

It was twisted, and wrong, but it was the only way to have her in his life and he wasn't quite ready to give her up. She stopped avoiding him, and even pranked him back which made his heart swell with pride (only to immediately deflate, because she would never be his). Still, they made this odd friendship work; they were constantly in each other's business, and he messed up her dates and she meddled in his life and it was just them.

It was the best he was going to get.

Then graduation came and he kept telling his dad that he was going to backpack across Europe, but really he was figuring out which schools Casey was applying to and figuring out those applications. He didn't get into every single school she did, but he got into most of them.

Getting her to eliminate the others from her consideration was a feat, though.

She announced he was going to Queens and he said the same and he could see relief in her eyes even though she played it off as she was annoyed. George and Nora thought it was a good idea, in order to save costs, for them to get an apartment together. They both made faces, but Derek was relieved. He wasn't sure if he'd be able to make excuses to see her.

And pranking would be so much easier when they shared a home.

They went apartment hunting and the only one they could agree on was the one where the two bedrooms shared a wall. Some things never change.

Sharing an apartment with Casey was easy, she cooked and so he begrudgingly cleaned the dishes and she cleaned up the rest of the apartment, without even realizing it. They fought over the remote, he pranked her, and living with her was easy and he felt that he was getting in deeper and deeper every day with this woman.

Then classes started and in some boring English class he shared it with a pretty blonde who reminded him, a little, of a combination of Sally and Casey. She caught his eye, he smirked, and she rolled her eyes smiling, turning back to her notes. She was there early the next time they had class and he dropped into the seat next to her. She looked at him expectantly, but he didn't say anything to her the entire class period. She raised a brow after the first five minutes, but turned ahead and focused on the lecture. He thought she'd make a pretty good distraction for awhile. After class was over, he gathered his things and headed out the door, but she called after him, and they talked, and she had depth and she was pretty and smart and passionate, and he found he enjoyed spending time with her, and suddenly she was with him all the time.

Derek and _Nancy_.

When they started dating, no one believed them when he said they met her in class ("Do you even go to class," Sam said when he heard the story). Casey believed him, though. Nancy came over to the apartment almost every day and she made an effort to get along with Casey and Space Case smiled weakly and pretended to make an effort and he couldn't figure out what the problem was. He knew she always preferred it when he dated anyone with a brain and he figured he'd get Casey's Stamp of Approval (which means everything to him, and how sick is that?) on this one, even though they weren't technically dating.

Until they were in Derek's room one evening and she looked up at him and said, "How come you never try to kiss me?" Her head tilting up at him.

"How come you never try to kiss me?" he countered and she giggled. It wasn't a stupid giggle that some girls did to make you think they thought you were funny; it was genuine and cute and he didn't mind it so much.

She leaned forward and tried to kiss him but it was clumsy and she nearly fell and she laughed again, and he smiled and pulled her to him, kissing her firm on the lips. A minute later he heard the front door open and close and they had the apartment to themselves.

So, yeah, he thought it would be Casey that he'd have a relationship progressing with, but since that first kiss, Nancy became nearly a constant presence in his life. He was fond of her, even more so than he had been of Sally (which was really saying something, even he could admit that). Sometimes, they fought, but Derek really hard to make it right because now he understood that sometimes couples fought and that was okay.

He went to Casey for advice, which felt a little wrong and even more messed up, but she always gave him sound advice and even the one time he messed up pretty bad with Nancy, he was able to fix it with Casey's help. Selfishly he was keeping her in his life, while also getting what he wanted from Casey with his girlfriend. Yet, he couldn't stand it when she went on dates. Casey had finally started to get along with Nancy (he had a feeling it had a lot to do with the fact that Nancy made him pick up after himself).

Second semester Nancy was over and they were watching a movie in the living room and Casey was in the kitchen and he laughed at something on the TV and his girlfriend looked over at him smiling. "What?" he asked, feeling her eyes on him.

"I love you," she sighed.

"I love you, too." And Derek had never been one to admit feelings without really meaning it, but he felt kind of trapped and he cared deeply for Nancy, and he felt he could grow to love her and was it possible to love two women at once? He sighed a little, realizing that he would have to bury his feelings for Casey way down deep because it wasn't fair to anyone, but this thought was cut short because one of the dishes broke in the kitchen, but she was.

"I'm fine," Casey called as they both turned to look at her, but she didn't sound fine and Derek got up to go and help her but Nancy smiled, said she'd handle it, and then she was in the kitchen with Casey and he was staring at the TV wondering what the fuck he'd done with his life.

On the weekends and Wednesday nights, Nancy started sleeping over. Casey started partying. It occurred to him to find it weird that he was having nights in and a stable monogamous relationship while the guys who came to pick up Casey varied frequently. Nancy expressed her concern about Casey's habits one night after they'd gone to bed. "She seems sad." Nancy sympathized, and then she brightened. "Maybe I could set her up with a friend of mine, she's going to have trouble meeting a nice guy this way."

Derek said nothing which Nancy took as acceptance. She brought the idea up to Casey the next day, "Derek and I were thinking," when did he get roped into this, "that you could go one a date with a friend of mine, Christian." She beamed, pleased with the plan. "He's smart and I'll bet you two get on famously."

Casey stared at them both, a blank look on her face as if she couldn't figure out _why_ this was happening. Then she blinked and shook her head. "No, I don't think I'm really interested in dating right now." She said something about being happy with where she was and disappeared into her room. Nancy deflated and Derek pulled her to his side to comfort her. He was relieved and upset at Casey's reaction. Selfishly he was relieved that she wasn't going to be dating anyone, and selfishly he was disappointed because it meant she would continue going out with strange guys doing goodness knows what.

He didn't like to think about what.

The day following this suggestion, Nancy and him were curled up to watch a movie and the apartment door opened, letting in an giggling, drunken Casey. She stumbled forward when another drunk bumped into her from behind and they both laughed as she caught her balance. Nancy looked sympathetic and Derek stared daggers at the guy-Charlie, a guy he knows from his media class who had bragged that he had _it_ in a bag this evening with a girl he'd been seeing at parties the past week or so. He hadn't realized it had been Casey. Misinterpreting his expression, Charlie grinned and apologized for interrupting. "My roommate is gone for the weekend," he attempted to whisper to Casey and she giggled, but it was fake and not Casey and she wouldn't take her eyes off of Derek's. Then Charlie tugged her hand, they both apologized as Charlie pointed out that they wanted to be alone, and they disappeared from the apartment.

He tried not to think about what they would be doing.

He doesn't even remember what happened the rest of the movie. Nancy tried to soothe him. "I know you feel protective over your step-sister," because she had learned that they would deny the word when it lacked the step, and unlike most people she could remember to use the step and Nancy was really the best for that, "but she's an adult, let her make her own choices.

"She's drunk," he pointed out and Nancy sighed, patting his hand.

"My brother is just as over protective," and Derek really hoped that wasn't the case because he knew his feelings didn't come from a place of sibling responsibility. When she went to bed, she didn't try to drag him with her knowing he'd be waiting up for a while. She did suggest he get some sleep, kissed his temple and left saying that she could sense a sibling squabble coming and it was best if she wasn't there for it.

He stayed up all night and was seriously grouchy when she snuck through the door the next morning. "Casey," he growled, the second he saw her messy brown hair poke through the door. She squinted at him, confused. "Where have you been?" And god, why did he feel like her parent?

She raised a brow and pretended to search the room and she must have read her mind. If he wasn't so mad, he'd probably smile. "Out." She kicked off her shoes, sighing. "What's up?"

How could she be so cavalier… except he didn't have a right to care this much, not this way. Still, he considered Casey to be his best friend and as her best friend he did have a right to be worried. Right? Right. "What's up?" he snapped and he saw a flash of guilt in her eyes before she steeled them. "You've been gone all freaking night with Mason," he went for a different name, testing a theory. "And I know his reputation. Dammit, Casey, I was worried about you." Her expression didn't change, the light didn't go out in his eyes.

"Well, I'm fine, and it was my idea. I suggested to Mason that we come here." She had wanted to have sex with him and Derek felt like his legs were going to give out on him, when had he stood up?

His expression hardened and he laughed with no mirth, "His name is Charlie."

"Really?" She seemed confused, "but you said-"

He cut her off, not letting her finish. "I was making a point." She scrunched up her nose, the way she did when she was trying to think and it was so damn cute it wasn't fair. "You don't even know his name; this isn't like you, Case."

Her eyes flashed and she snapped at him, "Yeah, well who says you even know me?" And he'd always been good at calling her bullshit so he knew that's what this was. Of course he knew her. He knew her better than anyone else, just as she knew him best (even better than Nancy, that he could admit).

He opened his mouth to say something else, but his phone rang and it was Nancy's ringtone (that had been her idea, but she'd been so excited about it, that he'd kept it), so he picked up the phone and Casey sneaked off to her room. She asked how Casey was, and he admitted he was worried, and Nancy cared and they talked about that until the subject of her birthday came up and she started dropping hints about what she would be expecting.

Casey showed up for the first half of the celebration, but she was strangely absent during the rest of the party. He'd like to say that it wasn't until the end of the night that he noticed she was gone, but he'd always been hyper-aware when it came to Casey so he knew the minute she'd walked out the door. She'd given Nancy a hug, said something that made his girlfriend smile and then disappeared out the door.

She was killing him, slowly.

They stayed in their apartment over the summer because Casey and Nancy both had internships and he had a part time job, but Nancy's roommate was moving out and was probably going to be living with some friends come the fall semester and she couldn't afford the rent, and somehow she convinced Derek it was a good idea that she move in with them.

He tried to talk her out of it, even though he wasn't even sure there was a reason not to, but he said that witnessing Casey with bedhead was not worth spending more time together, and she'd bear witness to some really ugly fights. Nancy had laughed and said that she didn't mind, because she'd already witnessed most of that and she'd love to get to know Casey better.

By this point Casey had stopped the serial dating, and most of the partying and she was returning to the keener Casey he knew and understood. So, he gave up and Casey came home and he announced that Nancy was going to be moving in with them. He thought, maybe, if he didn't ask for her opinion and just assumed her permission was a given she'd get mad and fight with him and he'd have to tell Nancy maybe next summer. But she smiled, her face too tight, as Nancy jumped up with a squeal saying it was so exciting and her arms were around Casey, and Casey looked close to tears as Nancy turned to beam at Derek and he smiled, weakly, back at Nancy. "Thrilling," Casey agreed, and he noted the sarcasm, but he didn't understand why she didn't argue with him.

He could have moved out into his own apartment with Nancy, but it would have left Casey without a roommate and he couldn't do that to her and he was a masochist and Nancy insisted she was fine sharing with both of them, "All that matters is I get to wake up to you every morning." She'd chirped and then planted a kiss on his cheek and ran off to call her mom (whom she told _everything_ ).

Because they were living together, he couldn't leave Nancy behind when they went to visit the family, and she insisted it was time they meet and he agreed. Everyone loved her, she was cheerful and upbeat and indulged Marti's games.

Living with his girlfriend and his best friend/step-sister was strange, because they both nagged at him to pick up his clothes, and they got along like sisters and more often than not he was the odd man out.

Sometimes Casey would be doing something and whatever it was, she'd always turn to look at him when his eyes were on her. Their eyes would meet and he'd get a vague picture of something and she'd have a half smile on her face and then Nancy would flounce into the room, and the guilt would eat at him, so he'd pull her in by the waist and giggle with her (which sounded strange to his ears, and he was ever grateful that to his knowledge Casey never shared this information with anyone), and he'd avoid looking at her, focusing intently on Nancy who would smile, and sigh happily in his arms and lean in for a kiss, which he would always meet with too much enthusiasm and when they finally surfaced for air, Casey would no longer be in sight and Nancy would laugh and look guilty, "Guess we scared her away," she'd joke and Derek would smile.

He loved Nancy, honestly. She was funny, energetic, smart, and beautiful, and she didn't always get him, but that was okay because she tried and she had endless patience. He started to think that spending the rest of his life with her wouldn't be the worst thing in the world.

Then he'd catch Casey's eyes at some point and he'd be drawn into those baby blues and he'd feel like he was being split apart into two. He never dared to ask himself the question: If you could be with Casey with no repercussions, would you leave Nancy?

He knew what the answer was, and so he never brought the conflict out of his subconscious. Life was better this way, and life still had Casey as long as she never knew.

The three of them continued living together and then suddenly it was graduation and the time had flown and he wasn't going to be living with Casey anymore. It was a rare moment of alone time with Casey and he found himself prolonging the moment. He had something to ask her, and he was more nervous about asking Casey than he was about asking Nancy. It was eating up at him until he finally pulled her into an alcove. He was distracted by their closeness for a moment, but he pulled out the ring he'd been hiding in his robes. "I want to ask Nancy to marry me," he said, "do you think she'll accept?" he opened the ring so she could see it and she looked dazed, nodding at him. He didn't feel relieved liked he thought he would, maybe a part of him had hoped that she would tell him it was a mistake, but it was only a small part because he'd given up on that dream years ago.

He smiled, bright, and looked relieved. "I knew you'd be the best one to ask, I wasn't sure what she'd say. Thanks, Case, that helps a lot." Casey was staring at the ring, probably wondering how he had afforded it and, being Casey, wondering when she would get hers. "It's beautiful, Derek." She said, sounding slightly off but he couldn't place the tone. When did he get so bad at reading her? "She'll love it." He let out a breath and they started heading back to where they were supposed to get ready for graduation, but Casey ducked into the girl's bathroom and he didn't see her again.

He guessed she must have snuck in, though, because they were starting and he didn't see her. They called the names and he found his family at some point (Lizzie's hair was hard to miss) and they smiled and waved and then Casey's name was called and they looked confused and he looked to the stage to realize that Casey was still absent.

She was going to be so pissed about missing.

He wanted to worry, but they had moved on and then it was his line going up and he had to worry about not tripping over the robes of the girl in front of him. She met up with them at the restaurant, though, and said she was worried about tripping. He laughed and called her Klutzilla but for some reason the whole thing felt forced. His dad started in on their plans for after school and Derek announced that he was going to be proposing to Nancy tonight.

None of them thought it was a bad idea. In fact, there was a lot of congratulations and excitement.

He drove her back to their apartment (where he learned that she had caught a ride to the restaurant). She was silent and he realized that maybe she was worried about no longer being his best friend and that's why she seemed so off since he announced the engagement, so he started babbling about how they'd be friends, and how he knew nothing about weddings and suddenly it was just out, "Would you be my best man?" As soon as he said it, he knew it was a great/terrible idea. She'd be the perfect person to plan a wedding he'd actually want to attend, knowing him so well, Nancy would want help, he knew, and it would show Casey that she was still his best friend.

"You want what?" She said, sounding slightly hysterical.

He glanced over at her, rubbing his neck and staring at her awkwardly. "I want you to be my best man…" whoops, maybe that's why she sounded upset, "... woman… person?" he tried, with a small smile. She shook her head just as they pulled up at the apartment. Nancy was already waiting for him, so they switched out and Casey disappeared into the apartment.

They went to a movie, all dressed up and then they walked around the mall before they finally went to dinner. She was in the bathroom, their dessert (Strawberry Cheesecake) had just been served with the strawberry sauce spelling out "Say Yes?" on the syrup. He looked confused and the waiter smiled, "Your sister called ahead, she thought you might need a little help." Derek smiled because it was the type of thing Casey would do.

When Nancy sat down, she picked up her fork, pleasantly surprised that Derek had waited for her before eating his half. She caught the words, though, and when she looked up at him, he had the box with the ring open. She shrieked, practically yelped her agreement, and then ran over to give him a hug. He stood just in time and was dimly aware of the clapping around them. Nancy looked radiant as he placed the ring on her finger.

Their dessert was free.

They move to their own apartment. Nancy gets a job in a publisher's office and he works as a marketing analyst. It's nice.

The wedding planning starts and Nancy gets this look in her idea anytime it comes up, but Casey is so good at being organized and dealing with Nancy that she insists Casey be the wedding planner. Casey was taken by surprise, but she agrees with only some hesitancy. Nancy is excited about the prospect about sisters and she calls Casey at least five times a day and Casey is patient and he doesn't hear one complaint. When he sees her, though, there's a tightness in her eyes and a falseness in her smile.

And Nancy is planning her bachelorette and he wonders if Casey knows he should have a bachelor party, except he doesn't really want one. She calls and asks what he'd like to do, and who he'd like to invite. He's honest (surprise, he can do that sometimes), and says he just wants to stay in, drink beer, and watch hockey. He doesn't get a lot of beer or hockey time since living with just Nancy. "What no strippers?" She teases, and there's a spark of the Casey from before, the one who didn't just exist in life, but who lived.

"Nah," that's never really been my thing." Which was true and he could feel her approval over the phone.

She showed up the night of Nancy's bachelorette and he knew that she'd encouraged Nancy to have it the night of one of the bigger games. He appreciated that. She had a case of beer in each hand, a hockey rule book tucked under her chin, and pizza already on the way (the latter part she explained as she shoved her way into his apartment, with the book still tucked under). He grinned at her, amused, and shut the door behind them.

They sat on the couch with the middle cushion between them and the beer on the coffee table in front of them. They ate pizza and Derek explained the rules of the game. She actually listened, holding her can of beer with both hands. It made her look vulnerable and he realized he couldn't remember the last time it was just the two of them hanging out.

"I can't believe I'm getting married in three weeks," he said, a little breathless. It seemed to hit him, just then.

"Yeah, me neither." She said, and she didn't sound the fake, perky happy that she'd been exuding the past months. She sounded bitter.

Something his dad had said rang in his ears (because George and Nora, as oblivious as they seemed sometimes, had noticed Casey wasn't herself, too) and Derek shifted, uncomfortably. "Everything okay, Case?" A commercial was playing so he looked from the TV to stare at her. "I know you haven't date in a while." She visibly cringed and he tried to remember the last date he knew about.

"I'm fine," she snapped and looked immediately guilty. "What does my dating life have to do with it?"

"I'm just saying, Case, you don't have to do all this wedding stuff if it makes you… uncomfortable."

"Why would it make me uncomfortable?" She said, the words coming out too fast, too defensive. He hadn't realized that maybe that's what had been bothering her after all.

He shrugged. "Some women get lonely when it comes to wedding and they're not with anyone... Look," he cut himself off, realizing that he was embarrassing himself and probably her, "it wasn't my idea, my dad said something about it." He wanted this conversation to be over.

"Oh."

They sat in silence for a momen, but he was still watching her. "Does it?"

"Does it what?" She asked, sounding annoyed. He didn't blame her.

He shrugged, watching her face. "Does it make you uncomfortable?" There was a beat, a pause, before she answered.

"No."

He said nothing, and she shifted in her seat. The living room was mostly dark with only the glow from the TV and a faint light from the kitchen. It was hard to read her expression, so he was studying intently when she whispered, "I love you."

He nearly fell off the couch. There was no way he had heard that correctly. "What?" He whispered, too. He was practically vibrating, and he was finding it near impossible to continue sitting still. Was he hearing things? Why did he hope so much that she'd said what he heard?

He saw the resolve in the way her posture stiffened, "I love you," she said, firmly, though her voice was still quiet. "I'm in love with you; I've known that since I was seventeen." She wouldn't look at him, though he was desperately pleading with his eyes for her to please look at him, because he has waited for this day for what feels like forever.

"Casey," he growled, when she wouldn't look at him. He was worried it was a joke, and he just needed to see her eyes, to know this wasn't some weird, bizarre trick.

She looked deflated. "I know I shouldn't have said anything, I've just been keeping it in for so long, I've had too much to drink." She'd only had two beers, but he could recognize a Casey freak out for what it was. "I don't even know why I said it, well I do know why." Her throat sounded closed up and he realized that she was going to cry, if she wasn't already. "It was killing me inside, piece by piece… but I won't say it, never again, I promise, Derek. After the wedding is over you'll never have to see me again, I'll be smiling and so happy for you on your wedding day, because I want you to be happy, I do. I'm so sorry. I promise, I won't ruin anything." She finally paused to take a breath. She started ringing her hands as a tear slid down her cheek.

"Casey," he says, again, more gently this time. Standing he kneels in front of her, grabbing her hands. "Casey," he said again, with more tenderness than he'd ever said anything. She blinked and the floodgates were open. He couldn't resist temptation any longer, not with a confession like that, not when she looked up at him and he felt his own eyes stinging with the heat of tears. He leaned forward, pulling her the rest of the way and their lips met.

It was the single, most perfect kiss in his mind. It was white hot, the spark between them finally ignited into a burning flame. She froze for only half a second before her hands were in his hair and she was kissing him back. Their lips together and it felt like he finally understood what it meant to breathe. He pulled away so he could kiss her neck and her cheeks as they tried to catch their breath. "I've wanted," he told her between kisses, "you," he trailed the length of her jaw, down her neck "since I've first met you." And he felt her shoulders shake. Her head was tilted to the side as he worked on her neck and suddenly she stiffened in his embrace.

Surprised, he paused and she pushed him away. He looked at her, hurt, wondering if maybe it had been a trick after all. "Nancy," she said, her voice sounding strangled again, and he saw the guilt in her eyes, because she liked Nancy and this, what they were doing, wasn't Casey. It wasn't Derek, either. The realization of what they had done and remembering Nancy (he's ashamed to admit that he'd forgotten all about her from the moment Casey admitted she loved him). He was washed with guilt and shame. "I should go," she said, still sounding half crazed. He didn't say anything, and she shot from the couch, grabbing her purse and jacket, running from the room.

For the briefest moment he had pictured a life with Casey more clearly than he ever had with Nancy. Surround sound, technicolor, etc. etc. It had felt right, and then someone had pulled the rug from under him as he remembered he was engaged to another woman. He was riddled with guilt, but he couldn't help focusing on the fact that it has been Casey all this time. It's always been Casey.

He sends her a text to at least let him know she made it home okay. Then, when she should have been home, he starts calling and it just rings and rings, so at least he knows that she's not directly ignoring his calls and instead his mind wanders and he worries that something happened because she took out of here like a bat out of hell. He cleans the apartment and can't stop picturing her car in a ditch or worse, so he keeps calling.

There's still no answer, and so he goes to her apartment but he can't find her car in the parking lot and that scares him more, so he calls her once more, sitting slumped outside of her apartment.

The next thing he knows he's waking to the sound of keys in the door and the pain from a crick in his neck. He jumped, forgot where he was for a second, and then spotted Casey trying to get into her apartment. He hurries to his feet. "Case." He's relieved she's safe, and he moves toward her.

She shakes her head, taking a step back for every one of his. She reminds him he's engaged, she tells him he hates her and he only half believes her because everyone knows there's a fine line between love and hate. The whole conversation hurts because if one of them had just spoken up, had just been honest, they could have been together long ago. She's been crying, he can tell, and he feels like there's a knife in his gut, slowly twisting around.

He never wanted to be the one to make her cry.

"Why couldn't you _see_? You were so, so fucking happy together," he doesn't think he's ever heard him curse, but he hurts too much to be surprised. "You could hardly tear your eyes from her, you were so disgustingly cute." It's another new one that she's disgusted by a cute relationship. "And then you brought her to live with us and it killed me every day seeing you together and you couldn't _see_ that I was in pain."

Except he had seen, he'd known something was different. If he'd just looked closer, maybe he would have seen. But she was the one girl who never fell for his charms, how was he supposed to know? He tried to explain how painful it was to pay more attention to Casey than to Nancy, how he threw himself into a relationship to ignore what she sparked him. It comes out inarticulate, but he makes her laugh.

Sort of.

She asks the question, and he knows it's going to cause her pain, but he's tired of lying, so he's honest. Yes, he loves Nancy. He's quick to add on, though, the rest of the truth, "But not like she should be loved, I've never been _in love_ with her, hard as I tried. I could never really, truly love anyone, because it's always you, Casey, it's always been you."

He expects a reaction, but not the one he gets. He's embarrassed as he realizes that he was settling with Nancy, but he's painfully honest, and he wishes she'd just let him in so they could stop having this conversation in the middle of her apartment hallway.

"Nancy is a wonderful person."

She's right, of course, she's a good person and she doesn't deserve him or them, and he says as much. She doesn't deserve to be with someone who thinks they're settling, and now that he's realized that, the thought is never going to go away. Casey says the words that kill him a little more.

"You should be with her, because she _does_ deserve better than this," as she gestures between the two of them. She has a point, but he doesn't care, "You chose her, you proposed to her, so now you need to give her the wedding and the marriage and you and I will awkwardly exchange pleasantries at holidays and leave it at that so you can focus on her and I can… focus on something else." She doesn't sound like Casey and he thinks he can get her to listen to reason if she would just listen to him. She doesn't, she insists he leave, and locks him out of the apartment.

He stands there looking at her apartment door for a few minutes. How is he supposed to get her to see that marrying Nancy when he's in love with someone else is _worse_ than canceling the wedding three weeks before. Then he thinks about everything Nancy has done for him, about what his parents would say if they canceled the wedding and if they ever found out the real reason why.

He leaves.

He's in a bad mood when he gets to work and if he cries behind his closed office door, that's no one's business. He's still in a bad mood and he can tell that Nancy is worried, but he can't bring himself to say anything of comfort.

She really does deserve better, and he's an ass.

The wedding is fast approaching, and anytime Nancy tries to talk to him about wedding stuff, he looks so apprehensive that she goes off and tries to call Casey. He snaps and tells her to give Casey a break, because now that he knows it pains him to think that she's been quietly planning his wedding while pining. Her eyes water and he gives her a kiss and tells her work is rough right now. She's appeased and he feels sick.

They get in another fight because he's not as interested in the wedding details as he was before. It's really about the fact that he won't have sex with her, but how can he when he's just picturing Casey? "It's like you don't even care," she cries.

He rolls his eyes and the words are out of his mouth before he can stop them. "Well, what if I don't even want to marry you." Though she apparently tells Casey he yelled it, the words come out calm, if a little shaky. Nancy looks shocked and Derek sighs before storming out of the apartment. He calls up Sam who knows better than to ask what's wrong, but he looks sympathetic and Derek wonders if he knows. They drink and play darts and if Derek's eyes get a little wet on the cab ride home, well the cab driver won't tell anyone.

He doesn't go to the bedroom he shares with Nancy, he makes it as far as the couch and passes out. He's awake, hungover, when Nancy leaves for work. He pretends to be asleep like the coward he is. When she's gone, he gets up and takes some Tylenol, drinks an entire cup of water, hops into the shower, and then passes out on the couch again. For some reason he can't bring himself to sleep in the bed he shares with his fiance. But he's always been a little fucked up.

When he nexts wakes up, it's afternoon and his stomach is growling for food. There's also a knock at the door and it's probably a combination of the two that wake him. He's cranky at being woken up, and hungry, but he hauls himself to the door, smiling when he realizes it's Casey.

Surprised, too, as she's been ignoring his calls. She looks at him, for only a moment, with adoration before she remembers she's mad and her eyes narrow and he knows she's mad, but she's so cute. They fight and it's not like their usual banter. He's mad now, and so is she. She's scared and that's why she won't just give them a chance. He wants to tell her as much, but he hasn't left Nancy so maybe he's scared, too.

She's stubborn, but so is he, but maybe she's right and he could never ask Casey to give up their family to be with him. And he wasn't sure he could give up seeing Marti.

He feels like shit, but he goes to a florist and gets a beautiful arrangement. He shows up at Nancy's work and she's angry (mostly hurt) when she sees him. He gives her a smirk, and sets up the flowers on her desk. Her expression softens but he's not forgiven. There's a speech, he admits to being scared, even if that's not what he was scared of. She forgives him, eventually, and when he's leaving he hears Nancy on the phone and he knows she's talking to Casey.

The knife in his stomach twists further.

The wedding is perfect. He shouldn't be surprised because Casey planned it, but he is surprised. Nora cries, a lot, and George just keeps patting him on the back. Casey is back to being Zombie!Casey with the happiest smile on her face. It's so fake he wants to shake her. She comes to check on him when he's getting ready, and the sight of her in a suit shouldn't knock the breath out of him, but it does. He's cuffs are crooked and he's struggling with his tie when she huffs and turns him to face her, "You're just making a mess of it," she explains with a roll of her eyes as she does his tie and then his cuffs. It's tense and awkward and they don't say much else. He's trying not to breathe because she's standing so close and smells so good, and she's trying not to make eye contact.

He doesn't see her during the ceremony because she's standing behind him the entire time and that's probably a good thing, because he's not sure he'd be able to take his eyes off her.

They're whisked off to take pictures, and then there's the ceremony and he's smiling so much his cheeks hurt and Nancy is so fucking happy and they're going around saying thanks to everyone. Somehow they miss saying thanks to Casey-at one point she's on one side of the room but when their rounds bring them over there, she's gone to the other side. He suspects she's avoiding them, but he doesn't blame her. Nancy doesn't notice. It's not so bad, and then they're about to cut the cake, but Nancy's cousin-her maid of honor-insists that she give a toast. She insists the same out of Derek, and he sees her eyes go wide as a microphone is thrust into her hands. Her toast is only slightly personal, just enough emotion, and if he didn't know better, he wouldn't think she was in love with him at all. He catches her eye during one part of the toast and he offers her a sad smile. Somehow he knows he won't be seeing much of her after the wedding. The wedding passes in a blur, and then they're on their honeymoon and suddenly he's _married_ , and honestly it's probably a good thing he doesn't see Casey because despite what some people believe of him, he does believe in the sanctity of marriage and now he's committed to Nancy.

He's right, though. They're married in March, he doesn't see her again until October, for Thanksgiving.

Casey opens the door in a burgundy knit dress and he's floored with how beautiful she looks. She's lost weight, though, too much. He doesn't have time to contemplate it too much, because Nancy is right behind him. He goes in for a hug as she gives him a little wave. He stops and nods, and she goes in for a hug only to pull away. They mumble a quick hello and he moves out of the way so Nancy can follow him inside. Edwin, Lizzie, and Marti bear witness to this entire awkward exchange and none of them seem to know what to make of it. He sees Lizzie corner Casey and when Marti tries to get the story out of him, he just shrugs.

Nancy overhears and she laughs, "I've been trying to get an answer from him for months," she admits.

They pretty much avoid each other the entire evening except for the brief moment they're alone in the kitchen. He had just taken a bite of a roll and she was being responsible and bringing in the dirty dishes and he tries to apologize at the same time she says, "Sorry, I…" He gives her an awkward grin and she offers a small smile and then they go off in their separate directions.

Being married is actually pretty great, until it isn't. Nancy wants kids. So does he, but he wants to be married a little while before they go that route. She wants to be a stay at home mom for a few years and the idea is appealing, but they can't afford that, not now.

They fight about it a lot.

He wants to call Casey, because she used to help them with their fights, but he doesn't. Nancy, it turns out, does e-mail Casey for advice. "I didn't want to tell you, because I know things are whatever between you, but she's still my friend."

He tells her not to bring Casey into it, "because it's none of her damn business what's going on with us." He just doesn't want to hurt her anymore.

A part of him wonders if the only reason they stayed together was because they had Casey as a buffer.

Around Halloween, Nancy goes by his childhood home to drop some things off. The next day, Nora is crying in tears because, "I can't believe I'm going to be a grandma," and he doesn't have the heart to tell her that they aren't trying, yet. Nancy shrugs it off and says that Nora misunderstood what she was saying, but she won't look him in the eye.

So, they start actively trying for a baby. Christmas comes around and things aren't going well-for the baby making, or their relationship. Nancy says she's not worried, but he knows she is. There's no sign of Casey during Christmas and finally he asks Marti why she's not there and she shrugs, saying Casey couldn't make it.

He wonders if she's with a boyfriend's family.

It doesn't take him long to realize that she's avoiding seeing him and Nancy. They're into the second year of his marriage and he tells Lizzie that he won't be able to make it to her birthday, because of work. She's understanding, "I just hope Casey can make it this year." And another knife joins the ones that have been stabbed into his stomach all those years.

"I'm sure she'll be there."

They still receive gifts and cards for birthdays, holidays, and their anniversary, because she's Casey and she can't not be Casey. He doesn't know that Nancy returns the gesture.

They still haven't had any luck with trying for a baby and Nancy blames him. She makes him get tested-it's a white, sterile room, and he's got a cup and it's awkward and not enjoyable at all, but he goes and (just as he knew it would) the test comes back saying his swimmers are fine. The tension increases when she thinks that maybe it's their fault.

Their doctor advises them to stop trying, because maybe it's the stress. So they stop trying, and sex becomes a little more enjoyable. They buy a house, because it's what they're expected to do.

Sheldon and Emily get married and they go to the wedding. Casey sits on the other side of the room from where he and Nancy are sitting. He tries to catch her eye, and he knows she's seen him because she actively won't look in his direction.

Years pass and things just get worse. Then Nancy gets pregnant and for a blissful few months, it looks like maybe their marriage will improve.

It doesn't.

Everything he does is wrong, and then Nancy loses the baby, and it's hard for them both. At first it's harder on their marriage, but the loss brings them closer together and Derek suggests marriage counseling (no one will believe it's his idea). He just wants to know they tried everything to make their marriage work. She agrees, so they go, and it helps.

He finds out that Casey is dating a guy. He chokes when he learns the guys name is Mason (he doesn't read much, but the irony isn't lost on him). Nora seems worried. "I just don't know. She sounds robotic every time I talk to her and half the time she seems confused about how the whole thing happened." Derek says nothing, but then Nora asks to talk to Nancy so he passes the phone and heads to the bathroom, just to have a break for a minute.

They have dinner once a week with his family and it's clear Nora grows increasingly frustrated that she hasn't met Mason. "Maybe he's not real," he jokes, and its something he would have said as a teenager that he looks up, half expecting a Der _ek_ from Casey and it's been so long since he's heard that. He frowns.

Nora sighs and starts planning the next opportunity to meet the guy. It's clear she thinks there are wedding bells in the future for these two, but she's smart enough to know Casey would never marry anyone who hasn't met the family, and maybe that's why Mason hasn't made it around the house. This doesn't seem to occur to Nora, "she just works too hard."

Christmas comes again and he and Nancy pull into the driveway next to an unfamiliar car. His heart leaps, despite the fact that he and Nancy are in yet another argument (he's not even sure what he's done wrong this time." She's talking to a tall, dark haired guy and it takes all his will power not to leap out of the car. They'd been sitting in silence the last five minutes of the ride, so he does get out in time to watch Casey stomp her foot like a child. "Casey, Casey is that you?" He said, dramatically. She turned, glaring at him and it's not at all awkward despite the fact he hasn't seen her in years. They're arguing, and bantering, and them and he can't help but smirk. He continues on, egging her on and he senses it before she even says it.

There's his name, falling from her lips with the emphasis on 'ek' and it feels like coming home. He can't help but laugh, despite the fact that she's glaring back at him. "Come on, Princess, you can't expect to be gone that long and not to get a lot of shit for it." He heard the door open as Nancy got out. "Nance, look who it is?" He's clearly amused, but Nancy isn't. She greets Case and shoots a glare at him and he remembers they are fighting, and apparently they aren't done, yet.

Casey has tact, so of course she starts to lead her boyfriend into the house, but Mason is clearly glad to meet the family. They aren't talking loud, but he can hear them clearly. Who's that?"

"Derek, my stepbrother… and his wife, Nancy."

"I thought Edwin was your stepbrother." Derek stiffened as he realized she'd been dating this dude for however long and he'd never been mentioned. Had she gotten over it that easily? Casey is rushing her boyfriend into the house now and it occurs to Derek that, maybe, had he been in her shoes, he wouldn't mention him either.

Nancy asks him if he thinks this marriage is worth fighting for, but he's too caught up in thinking about Casey that he misses the question, and she takes that as her answer. It's too late by the time the words finally catch up to him and by then, she's already heading for the door. The family was still in the middle of greeting and he saw Lizzie pocket some money. There was a glare for her and Edwin for betting on his marriage.

Mason clearly enjoyed the chaos of the McDonald-Venturi household. Despite being grown now, and Marti being the only one in college, they all bickered like children and when he finally succeeded in meeting Casey's eye, he smiled because she looked so happy to be home and he was happy to see her. She smiled back and he regretted a lot of decisions in that moment. He couldn't help but glare at Mason, as he seemed oblivious to how Casey was feeling and he watched her surprise as she realized the rooms were sorted and the presents were already here.

She had no intention of being here this Christmas, but Mason had gone through a lot of trouble.

They all got ready for bed, and for some reason Edwin, Lizzie, Casey, and Derek were all fighting over who got to take a shower. Marti didn't partake, because she knew better, and Nancy and Mason looked on with amusement, not daring to interrupt.

His dad grumbled downstairs and Edwin mumbled something about old habits and Casey caught _his_ eye and they smiled, and the four of them were laughing. Nancy was in a better mood when they finally made it into bed.

He woke up in the morning to Nancy kissing his face. "Merry Christmas," she murmured. He smiled, glad she was in a good mood.

"Merry Christmas." he murmured back. There were feet on the stairs and Marti yelling about presents and she laughed.

"I can't wait until we have the pitter patter of feet and our kids yelling about their Christmas presents." He grinned, and he could picture it but the kids in his mind had Casey's blue eyes.

"Yeah," he agreed. She didn't notice his absent mindedness, or if she did she didn't comment on it. They got dressed.

Once they were downstairs, the unveiling of presents began. There were sounds of tearing paper and excited squeals over what they'd received, and quiet thanks. Nancy and Nora were cooing over the new bracelet the latter had just received. Derek sat beside Casey. "Merry Christmas, Princess," he muttered.

"Merry Christmas, Derek," she whispered back and he slipped a small box into her hands. It wasn't anything special, just a new charm for her bracelet. He returned to his seat as Mason pointed out a gift that Casey had missed. The boy was shaking so hard, and Nora had grabbed a camera and Derek _knew_ what was about to happen. Casey was too oblivious to see it coming. She thought the gift was just a sweater, and as Mason slid onto one knee, delivering the sappiest proposal Derek had ever heard, he watched her.

Her eyes were wide, the proverbial deer in the headlights look. She hadn't seen this coming. Derek was more surprised that it had taken this long to happen, but then he knew Casey had been avoiding bringing Mason home. The thought of Casey being married to someone else fueled him with angry, and he knew she saw it in his eyes. She looked afraid, and she had some sort of realization because a light reached her eyes. Then, without warning, she bolted from the house.

The clicking from Nora's camera stopped, and they all exchanged looks. Mason was red in the face as he stood up. "Uh," he looked to the door.

"Oh, just give her a minute," Nora said, sympathetically. "It was out of the blue, and she probably didn't think you were going to propose." Her way of saying it should have happened sooner.

"She's always had a flare for the dramatics," Derek quipped. His voice sounded strange to him, but no one seemed to notice.

When she came back inside, her eyes were red and everyone was staring at her. She didn't say anything, only headed up the stairs. Mason followed. Derek looked around and, in an effort to break the ice (not because he's selfish like everyone suspected), asked, "What's for breakfast?" Nancy hit him on the arm and he shrugged. The comment did spur people into action, though.

They were in the middle of fixing breakfast when Mason and Casey came back downstairs. Both were dressed and Mason still looked lost as he helped bring their luggage down.

After they left, Lizzie and Edwin were busy whispering over betting why the wedding was broken off. Marti was watching Derek, but he didn't get why. Breakfast was awkward and Derek and Nancy left in the afternoon.

A week later, they sat in their kitchen working through a silent dinner. "Nancy," Derek started. She looked up at him, annoyed from their earlier argument. He took it as his cue to continue. "Last week, Christmas Eve, you asked if I thought this marriage was worth fighting for."

He paused, because he thought she was going to interrupt, but she said nothing, blinking at him. His voice broke as he said, "I don't think it is."

"Oh."

It was his turn to give her a blank look. _Oh_ , that's all she had to say. She shrugged and he started to apologize. "Don't, Derek." She sighed, her shoulders slumping, "I'm honestly relieved."

"Oh."

She gave him a tired smile, "I'm just… tired of fighting all the time and I think I wanted so badly to make it work, but if you have to work that hard at something, it was going to end eventually."

He's relieved, and a little hurt, but he imagines she feels the same way. "We tried," he said and she nods in agreement. It was the first time they had agreed on something in a long time.

The divorce is simple, and involves a lot less fighting than their marriage and they're happy with how it ends. He hears from Marti that Mason and Casey had broken up. "Not that it was much of a surprise," she said. "She went that long without bringing him home, he was never going to last." Derek agreed, but he didn't say anything.

He went to weekly dinner without Nancy for the first time and everyone just knew. He asked that they not mention it to Casey and he saw Lizzie slide some money to Edwin. "Why?" George asked and Nora shook her head at him.

"Because he finally realized he loves her." He didn't bother correcting them that he'd known for a lot longer. Mostly he's in shock that everyone is so okay with it. It kind of hurts, because they could have been together a long time ago. Edwin is triumphant, because he knew that Derek would be the first to admit his feelings, and then Derek's forced to sheepishly admit that Casey was the first to admit it all those years ago. Understanding dawned on them all and Edwin grudgingly gave Lizzie her money back and handed over his bet.

He wants to tell her in person, so he waits, but it seems she's back to avoiding him. Instead of waiting for a holiday, he waits until he knows that she's going to be there on an innocuous weekend in March. Somehow it gets back to her that he's going and Casey cancels her plans last minute.

He had waited ten months, no he's waited fifteen years to be with Casey. He decides not to wait any longer, and he shows up to her apartment in London. She opens the door, confused, and he's angry letting himself in.

They fight, of course they do, they always fight, but he's enjoying himself (he's also mad that she's still been avoiding him) and he sees that she is, too. God, how he missed her, missed this.

She calls him names, and when she asks why his divorce matters to her, he's hurt and for a moment he thinks that maybe time has changed her feelings. He can see the pain in her eyes and he knows that she's just as tired as he is. Tired of pretending that they feel nothing for one another, tired of being apart.

He steps close to her, they're touching, but he doesn't kiss her. "And what if you're what makes me happy?" He points out, and he knows she doesn't want to argue with that logic. He wants to kiss her, hold her, because it's been too long. He doesn't, though. "I love you."

"I hate you," she mutters back, but the tone of voice she uses does not sound like hate, so he brushes her lips against hers. It's not quite a kiss, but it's enough for her to breathe, "I love you."

It's all he needs, pressing his lips to her in a firm kiss. It was better than he remembered and the stabbing pain in his stomach receded because this was right, this was meant to be. It happened very fast, but it had been building for nearly fifteen years. He lifted her up and her legs wrapped around his waist, and stumbled off into her bedroom. It was clumsy, and there was more banter, but it was perfect and them and he loved every second. He felt like he was in college again.

It wasn't until later when he felt her tense up beside him and he sensed an impending Casey Freak Out. "Derek," her tone was tense and he sighed, pulling her to him so he could kiss her temple.

"Stop worrying about it. Our parents and siblings aren't going to shun us."

"You don't know that."

"Casey, I'm tired of pretending you're not the one I want to be with."

She sighed. "I am, too."

He smiled, pressing another kiss to her temple. "Beside, they already know." She pulled away, sitting up on her elbow to look at him, and he shrugged. "I told them after me and Nancy divorced." He watched it dawn on her that they really could have been together all this time and he explained how there had been _bets_ about who would crack first.

Casey cried when she realized that if she hadn't been avoiding him, they could have been together sooner. She cried harder when she realized that they could have been together, at least, in college. When she'd settled, he whispered in her ear, "I haven't been this happy in a very long time, Casey." She positively beamed at him, and honestly that smile made everything worth it.

They were married a month later. They had wasted enough time and they were both sure that this is where they were meant to be. The ceremony was small, with just their close friends and family in attendance. It wasn't what he expected Casey wanted, but she'd smiled when he mentioned and said, "The idea of a big, perfect wedding was Teenage Casey, all I want is you." He called her a sap, but he was smiling the rest of the day.

The day of the wedding he never left her side, in fact they were always touching some way. His hand on the small of her back or her hand on his shoulder or knee.

They still, fought, of course, and it wasn't a perfect life but it was the one he wanted. They buy a house closer to their parents and they had three kids, two girls and a boy. He pretends to hate that he is outnumbered by the girls in the family and they all tease him.

He keeps in contact with Nancy, oddly enough, for a short while. She found love, too, and she was happy for Derek and Casey when she found out, saying she wished she'd seen it sooner to save them all a bunch of heartache. There were certainly regrets on all parties, but he was glad that Nancy didn't blame him, or Casey.

The stabbing pain that had plagued him for years was gone and he woke up most mornings reaching for Casey, just to assure himself that it's real. Of course, most mornings she's awake and out of bed before him but it's not until he hears her calling after their son to pick up his clothes off the floor that he's relieved, falling back onto the bed grateful they'd finally stopped wasting time.


End file.
